You can use Firebase Remote Config to define parameters in your app and update their values in the cloud, allowing you to modify the appearance and behavior of your app without distributing an app update. This guide walks you through the steps to get started and provides some sample code, all of which is available to clone or download from the firebase/quickstart-android GitHub repository.
Step 1: Add Firebase and the Remote Config SDK to your app
If you haven't already, add Firebase to your Android project.
For Remote Config, Google Analytics is required for the conditional targeting of app instances to user properties and audiences. Make sure that you enable Google Analytics in your project.
In your module (app-level) Gradle file (usually
<project>/<app-module>/build.gradle.kts
or<project>/<app-module>/build.gradle
), add the dependency for the Remote Config library for Android. We recommend using the Firebase Android BoM to control library versioning.Also, as part of setting up Analytics, you need to add the Firebase SDK for Google Analytics to your app.
dependencies { // Import the BoM for the Firebase platform implementation(platform("com.google.firebase:firebase-bom:33.4.0")) // Add the dependencies for the Remote Config and Analytics libraries // When using the BoM, you don't specify versions in Firebase library dependencies implementation("com.google.firebase:firebase-config") implementation("com.google.firebase:firebase-analytics") }
By using the Firebase Android BoM, your app will always use compatible versions of Firebase Android libraries.
(Alternative) Add Firebase library dependencies without using the BoM
If you choose not to use the Firebase BoM, you must specify each Firebase library version in its dependency line.
Note that if you use multiple Firebase libraries in your app, we strongly recommend using the BoM to manage library versions, which ensures that all versions are compatible.
dependencies { // Add the dependencies for the Remote Config and Analytics libraries // When NOT using the BoM, you must specify versions in Firebase library dependencies implementation("com.google.firebase:firebase-config:22.0.0") implementation("com.google.firebase:firebase-analytics:22.1.2") }
Step 2: Get the Remote Config singleton object
Get a Remote Config object instance and set the minimum fetch interval to allow for frequent refreshes:
Kotlin+KTX
val remoteConfig: FirebaseRemoteConfig = Firebase.remoteConfig val configSettings = remoteConfigSettings { minimumFetchIntervalInSeconds = 3600 } remoteConfig.setConfigSettingsAsync(configSettings)
Java
FirebaseRemoteConfig mFirebaseRemoteConfig = FirebaseRemoteConfig.getInstance(); FirebaseRemoteConfigSettings configSettings = new FirebaseRemoteConfigSettings.Builder() .setMinimumFetchIntervalInSeconds(3600) .build(); mFirebaseRemoteConfig.setConfigSettingsAsync(configSettings);
The singleton object is used to store in-app default parameter values, fetch updated parameter values from the backend, and control when fetched values are made available to your app.
During development, it's recommended to set a relatively low minimum fetch interval. See Throttling for more information.
Step 3: Set in-app default parameter values
You can set in-app default parameter values in the Remote Config object, so that your app behaves as intended before it connects to the Remote Config backend, and so that default values are available if none are set in the backend.
Define a set of parameter names and default parameter values using a Map object or an XML resource file stored in your app's
res/xml
folder. The Remote Config quickstart sample app uses an XML file to define default parameter names and values.If you have already configured Remote Config backend parameter values, you can download a generated XML file that includes all default values and save it to your app's
res/xml
directory:REST
curl --compressed -D headers -H "Authorization: Bearer token" -X GET https://firebaseremoteconfig.googleapis.com/v1/projects/my-project-id/remoteConfig:downloadDefaults?format=XML -o remote_config_defaults.xml
Firebase console
In the Parameters tab, open the Menu, and select Download default values.
When prompted, enable .xml for Android, then click Download file.
Add these values to the Remote Config object using
setDefaultsAsync(int)
, as shown:Kotlin+KTX
remoteConfig.setDefaultsAsync(R.xml.remote_config_defaults)
Java
mFirebaseRemoteConfig.setDefaultsAsync(R.xml.remote_config_defaults);
Step 4: Get parameter values to use in your app
Now you can get parameter values from the Remote Config object. If you set
values in the backend, fetch them, and then activate them,
those values are available to your app. Otherwise, you get the in-app
parameter values configured using
setDefaultsAsync(int)
.
To get these values, call the method listed below that maps to the data type
expected by your app, providing the parameter key as an argument:
Step 5: Set parameter values in the Remote Config backend
Using the Firebase console or the Remote Config backend APIs, you can create new server-side default values that override the in-app values according to your desired conditional logic or user targeting. This section describes the Firebase console steps to create these values.
- In the Firebase console, open your project.
- Select Remote Config from the menu to view the Remote Config dashboard.
- Define parameters with the same names as the parameters that you defined in your app. For each parameter, you can set a default value (which will eventually override the corresponding in-app default value), and you can also set conditional values. To learn more, see Remote Config Parameters and Conditions.
Step 6: Fetch and activate values
- To fetch parameter values from the Remote Config backend, call the
fetch()
method. Any values that you set in the backend are fetched and stored in the Remote Config object. To make fetched parameter values available to your app, call the
activate()
method.For cases where you want to fetch and activate values in one call, you can use a
fetchAndActivate()
request to fetch values from the Remote Config backend and make them available to the app:Kotlin+KTX
remoteConfig.fetchAndActivate() .addOnCompleteListener(this) { task -> if (task.isSuccessful) { val updated = task.result Log.d(TAG, "Config params updated: $updated") Toast.makeText( this, "Fetch and activate succeeded", Toast.LENGTH_SHORT, ).show() } else { Toast.makeText( this, "Fetch failed", Toast.LENGTH_SHORT, ).show() } displayWelcomeMessage() }
Java
mFirebaseRemoteConfig.fetchAndActivate() .addOnCompleteListener(this, new OnCompleteListener<Boolean>() { @Override public void onComplete(@NonNull Task<Boolean> task) { if (task.isSuccessful()) { boolean updated = task.getResult(); Log.d(TAG, "Config params updated: " + updated); Toast.makeText(MainActivity.this, "Fetch and activate succeeded", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(MainActivity.this, "Fetch failed", Toast.LENGTH_SHORT).show(); } displayWelcomeMessage(); } });
Because these updated parameter values affect the behavior and appearance of your app, you should activate the fetched values at a time that ensures a smooth experience for your user, such as the next time that the user opens your app. See Remote Config loading strategies for more information and examples.
Step 7: Listen for updates in real time
After you fetch parameter values, you can use real-time Remote Config to listen for updates from the Remote Config backend. Real-time Remote Config signals to connected devices when updates are available and automatically fetches the changes after you publish a new Remote Config version.
Real-time updates are supported by the Firebase SDK for Android v21.3.0+ (Firebase BoM v31.2.4+).
In your app, use
addOnConfigUpdateListener()
to start listening for updates and automatically fetch any new parameter values. Implement theonUpdate()
callback to activate the updated config.Kotlin+KTX
remoteConfig.addOnConfigUpdateListener(object : ConfigUpdateListener { override fun onUpdate(configUpdate : ConfigUpdate) { Log.d(TAG, "Updated keys: " + configUpdate.updatedKeys); if (configUpdate.updatedKeys.contains("welcome_message")) { remoteConfig.activate().addOnCompleteListener { displayWelcomeMessage() } } } override fun onError(error : FirebaseRemoteConfigException) { Log.w(TAG, "Config update error with code: " + error.code, error) } })
Java
mFirebaseRemoteConfig.addOnConfigUpdateListener(new ConfigUpdateListener() { @Override public void onUpdate(ConfigUpdate configUpdate) { Log.d(TAG, "Updated keys: " + configUpdate.getUpdatedKeys()); mFirebaseRemoteConfig.activate().addOnCompleteListener(new OnCompleteListener<Boolean>() { @Override public void onComplete(@NonNull Task<Boolean> task) { displayWelcomeMessage(); } }); } @Override public void onError(FirebaseRemoteConfigException error) { Log.w(TAG, "Config update error with code: " + error.getCode(), error); } });
The next time you publish a new version of your Remote Config, devices that are running your app and listening for changes will call the
ConfigUpdateListener
.
Throttling
If an app fetches too many times in a short time period, fetch calls are
throttled and the SDK returns
FirebaseRemoteConfigFetchThrottledException
. Before SDK version 17.0.0, the
limit was 5 fetch requests in a 60 minute
window (newer versions have more permissive limits).
During app development, you might want to fetch and activate configs very
frequently (many times per hour) to let you rapidly iterate as you develop and
test your app. Real-time Remote Config updates automatically bypass the
cache when the config is updated on the server. To accommodate rapid iteration
on a project with up to 10 developers, you can temporarily set a
FirebaseRemoteConfigSettings
object with a low minimum fetch interval
(setMinimumFetchIntervalInSeconds
) in your app.
The default minimum fetch interval for Remote Config is 12 hours, which means that configs won't be fetched from the backend more than once in a 12 hour window, regardless of how many fetch calls are actually made. Specifically, the minimum fetch interval is determined in this following order:
- The parameter in
fetch(long)
- The parameter in
FirebaseRemoteConfigSettings.setMinimumFetchIntervalInSeconds(long)
- The default value of 12 hours
To set the minimum fetch interval to a custom value, use FirebaseRemoteConfigSettings.Builder.setMinimumFetchIntervalInSeconds(long)
.
Next steps
If you haven't already, explore the Remote Config use cases, and take a look at some of the key concepts and advanced strategies documentation, including: